Rust-inhibited calcium base greases

ABSTRACT

This disclosure concerns calcium base greases containing a rustinhibiting amount of a combination of lead naphthenate and didodecyl dimethyl quaternary ammonium nitrite (or nitrate). Preferably, the grease contains, also, a fatty imidazoline alkyl diamine dicaprylate. These greases are particularly suitable for use in salt-water environments.

United States Patent William Patrick Scott Ponca City, Okla. 729,425

May 15, 1968 Nov. 30, 1971 Continental Oil Company Ponca City, Okla.

Inventor Appl. No. Filed Patented Assignee RUST-INHIBITED CALCIUM BASE GREASES 8 Claims, No Drawings U.S. Cl 252/313, 252/34, 252/34.7, 252/36, 252/389, 252/392 Int. Cl Cl0m 5/22, C10m 5/20 Field of Search 252/34,

Primary E.raniiner-Daniel E. Wyman Assistant E.raminerl. Vaughn Attorneys-Joseph C. Kotarski, Henry H. Huth, Jerry E.

Peterson, Bayless E. Rutherford, Jr. and Carroll Palmer ABSTRACT: This disclosure concerns calcium base greases containing a rust-inhibiting amount of a combination of lead naphthenate and didodecyl dimethyl quaternary ammonium nitrite (or nitrate). Preferably, the grease contains, also, a fatty imidazoline alkyl diamine dicaprylate. These greases are particularly suitable for use in salt-water environments.

RUST-INHIBITED CALCIUM BASE GREASES BACKGROUND Historically, calcium base greases were the first to be commercially produced in any volume. Over the years they have had the largest sale of any of the greases and continue to be popular. The reason for this large consumption is that they are economical, have good resistance to water, are stable at most temperatures ordinarily encountered and have a smooth texture.

Since calcium base greases have good resistance to water they are particularly suitable in marine applications. ln the past it has been customary to incorporate a rust inhibitor in the grease to improve its resistance to corrosion. Most of the rust-inhibited greases of the prior art, including those which are commercially available, provide reasonably satisfactory service in fresh water. Unfortunately, in salt-water, or brackish water, the greases of the prior art are not too satisfactory. Accordingly, it is highly desirable to have a calcium base grease which provides outstanding rust inhibition in a saltwater environment.

it is an object of the present invention to provide such a grease.

PRIOR ART The use of lead naphthenate in greases is well known. For example, U.S. Pat. No. 3,355,384 teaches a lithium base grease containing a rust inhibiting amount of a combination of lead naphthenate and a petroleum oxidation product.

U.S. Pat. No. 3,159,564 teaches the use of quaternary ammonium compounds (e.g. dicocodimethyl ammonium chloride) to improve the yield of calcium base greases. This patent, however, contains not teachings that quaternary ammonium compounds are useful as a rust inhibitor.

To my knowledge there are no references which teach a grease composition containing a combination of lead naphthenate and didodecyl dimethyl ammonium nitrite, or of this combination containing, in addition, a fatty imidazoline alkyl diamine dicaprylate.

BRIEF SUMMARY OF THE INVENTION Broadly stated, my invention relates to calcium base greases containing a rust-inhibiting amount of a combination of lead naphthenate and dialkyl dimethyl quaternary ammonium nitrite (or nitrate).

in a preferred embodiment, my invention relates to calcium base greases containing a rust-inhibiting amount of a combination of lead naphthenate, dialkyl dimethyl quaternary ammonium nitrite (or nitrate) and a fatty imidazoline alkyl diamine dicaprylate.

Preferably, the dialkyl dimethyl quaternary ammonium nitrite is didodecyl dimethyl quaternary ammonium nitrite.

In one aspect, my invention relates to a method of lubricating machinery exposed to a salt-water environment wherein the lubricant is a calcium base grease containing a rust-inhibiting amount of a combination of lead naphthenate, dialkyl dimethyl quaternary ammonium nitrite (or nitrate) and a fatty imidazoline alkyl diamine dicaprylate.

DETAILED DESCRIPTION Calcium Base Greases Suitable calcium base greases for use in my invention include calcium soap greases and calcium sulfonate greases. The term "calcium soap greases includes hydrate, anhydrous and complex greases. The book Manufacture and Application of Lubricating Greases by C. .l. Boner (Reinhold Publishing Corp., pages 355-423 and Corp. New York, 1954) 640-649 describes calcium soap greases. in order to make my disclosure more complete these portions of the Boner book are made a part of this disclosure.

The calcium soap greases comprise a grease-forming amount of a calcium soap or calcium complex in a liquid lubricating oil. The amount of calcium soap or calcium complex is suitably in the range of about 1 to about 25 percent by weight of the base grease. Preferably, the amount of calcium soap or calcium complex is in the range of about 5 to about 10 percent, by weight.

The liquid lubricating oil which is used in the calcium base greases of my invention can be either a mineral lubricating oil or a synthetic lubricating oil. Of these, the mineral lubricating oils are preferred. These can be derived from naphthenic or paraffinic base crude oils, and can be either residual or distillate oil or a mixture thereof, depending on the particular grease which is being prepared.

The term synthetic lubricating oil, as used herein, refers to materials derived synthetically which are suitable as lubricants. Examples of suitable synthetic lubricants include the silicones, polyalkylene glycols, fluorocarbons, esters of dicarboxylic acids, esters of long-chain carboxylic acids, and complex esters.

It is to be understood that the type of lubricating oil used in my greases is not critical, and that any of the lubricating oils which have heretobefore been used to prepare calcium base greases are suitable.

The term calcium sulfonate" grease refers to greases wherein the grease-forming agent is a calcium sulfonate. Preferably, the grease-forming agent is a hyperbasic calcium sulfonate. (The term hyperbasic means that the calcium sulfonate contains an excess of basic calcium compounds over that required to neutralize the sulfonic acid.)

An example of a suitable calcium sulfonate grease and a method of preparing same is taught by McMillen in U.S. Pat. NO. 3,242,079, which patent is made a part of this disclosure.

An alternative and particularly suitable process of preparing the calcium sulfonate grease is disclosed and claimed in application Ser. No. 727,719 filed May 8, 1968, and now abandoned which application is made a part of this disclosure.

It is to be understood that the present invention concerns only the rust-inhibited grease composition and not the process of preparing the calcium base grease.

The calcium sulfonate greases, preferably, have the following composition:

Suitable Preferred Nonvolatile diluent oil 20-80 40-60 Dispersing agent 5-55 15-30 Basic calcium compound l-45 3-35 These greases have a dropping point, ASTM, of at least 480 F. In addition they have an acetic base number of at least 50, preferably at least 135.

The tenns nonvolatile diluent oil" "dispersing agent and basic calcium compound are described in the above-mentioned application. They are also described in U.S.

No. 3,150,088, which patent is made a part of this disclosure.

Since the rust-inhibiting additive combination of my invention has been found to be suitable in several different types of calcium base greases, it is believed to be suitable for use in all calcium base greases.

Rust-inhibiting Additive Combination Lead N aphtenate The lead naphthenate which is used in the greases of my invention can be any commercially available lead naphthenate. A commercial grade of lead naphthenate containing about 30 percent, by weight, lead has been particularly suitable. Quaternary Ammonium Nitrite (or Nitrate) The dialkyl dimethyl quaternary ammonium nitrite or nitrate which is used in the greases of my invention can be represented by the following formula:

wherein X is nitrite or nitrate and R and R are C, to C,-, groups. Preferably, R and R are C to C alkyl groups and X is nitrite. When he material is derived from coconut oil or tallow, R and R, may be referred to as dicoco and ditallow.

A particularly suitable material is didodecyl dimethyl quaternary ammonium nitrite which is available from Armour Industrial Chemical Company under the trade name Arquad 2 C Nitrite.

Arquad 2 C Nitrite has the following composition and properties:

Fatty lmidazoline Diamine D icaprylate This material is the reaction product of l or 2 moles (preferably 2 moles) of caprylic acid and a fatty imidazoline alkyl diamine. The fatty imidazoline alkyl diamine is represented by the following structural formula:

wherein R is a mixed heptadecenyl (oleic) or mixed heptadecadienyl (linoleic).

A particularly suitable material is available from Nalco Chemical Company under the trade name Nalco G39M. Relative Amounts of Materials in Rust-Inhibiting Additive Combination The amounts of the materials which are used in the greases of my invention are as follows (in percent by weight of total grease composition):

More

Suitable Suitable Preferred Lead Naphthenate 1-3 1.5-2.5 2.0 Quaternary Ammonium Nitrite or Nitrate 1-4 1.25-2 1.5 Fatty imidazoline alkyl diarnine dicaprylare 0.5-2 0.75-1.25 1.0

Illustrations and Comparisons In order to disclose the nature of the present invention still more clearly, the following illustrative and comparative examples will be given. It is to be understood that the invention is not to be limited to the specific conditions or details set forth in these examples except in so far as such limitations are specified in the appended claims.

Rust Test Method The rust test method which was used to evaluate the calcium base grease, containing various rust inhibitors, was a modification of ASTMD-l743-64. Since the original method is quite mild it was modified to provide a more severe method. First, the method was modified by substituting lake water, sea water or synthetic sea water (ASTM Method D665-1P135 gives composition) for the distilled water called for by the original method. Secondly, the severity of the method was increased by the following changes in the thrust-loaded. run-in procedure:

a. after the 10 second rotation period the bearing was immersed in salt water for 10 seconds (Section 8f, ASTMD 1743-64);

b. the bearing was then rotated a second time in accordance with paragraph 8h and again immersed in salt water.

Following (b) the bearing assembly was placed in a glass jar to which 5 ml. of salt water had been added. The jar was sealed and stored in a dark cabinet at 77 F. for a specified time.

in summary, the original ASTM method specifies that the test bearing, packed with 2 grams of grease and rotated, be dipped in distilled water just prior to storage in a sealed jar over 5 ml. of distilled water. The severity of the test has been increased by (1) immersing the packed bearing in salt water, (2) rotation under a thrust load to distribute fully the salt water, (3) a second immersion in salt water, and (4) storage in salt water environment.

While the original ASTM test specifies two weeks storage time prior to examination for rust, l have found that poorly inhibited greases are completely corroded in one week or less. Because of this most testing was limited to a one week's storage time.

In the examples the term parts" refers to parts by weight.

EXAMPLE 1 The base grease used in this example was a calcium sulfonate grease having the following composition:

55 percent hyperbasic calcium sulfonate* 44.7 percent bright stock lubricating oil 0.3 percent oxidation inhibitor The hyperbasic calcium sulfonale used to prepare this grease had an acetic base number ofabout 300.

This base grease gave a N0. 3 fail rating (severe rusting) when tested using the original ASTM test method, employing distilled water after 2 weeks storage. The base grease failed the modified ASTM test, using synthetic sea water, in that after one weeks storage there was almost percent corrosion of all bearing surfaces.

A grease consisting of 98 percent base grease and 2 percent lead naphthenate passed the original ASTM test, giving a No. 1 pass. This lead naphthenate-containing grease when tested using the modified ASTM method with synthetic sea water resulted in corroded bearings but not as severe as that obtained using the base grease alone.

EXAMPLE 2 Quaternary Ammonium Nitrite Rusting alter One Week Storage 05 Severe rusting 1.0 Light to moderate 1.5 No rust to light rusting 2.0 No rust to trace 4.0 No rust to trace 6.0 Trace rust and stain EXAMPLE 3 This example illustrates the rust-inhibiting effect of a combination of lead naphthenate and didodecyl dimethyl quaternary ammonium nitrite (Aquad 2C Nitrite) in varying amounts in the calcium sulfonate grease of example 1.

This example also illustrates the rust-inhibiting effect of a combination of lead naphthenate, didodecyl dimethyl quaternary ammonium nitrite (Arquad 2C Nitrite) and fatty 2.0% (wt.) lead naphthenate 1.5% (wt.) didodecyl dimethyl quaternary ammonium nitrite 1.0% (wt.) fatty imidazoline alkyl diamine diamine dicaprylate' 5 Arquad" 2C NO, imidazoline alkyl diamine dicaprylate (Nalco 639M), in vary- I ing amounts in the calcium sulfonate grease of example 1. SCC

The modified ASTM test, using salt water, was employed. Th compounded grease a te ted using the m difi d The results were as f ll W I A. ASTM method, employing lake water (Lake Ponca, Ponca WT PERCENT IN BASE GREASE 10 City, Okla.). One of the better commercial greases was tested concurrently for comparative purposes. The results were as Fatt imld Quaternary zolt r ie 81151 Salt water rustfollows Lead ammonium diamine ing after one naphthenate nitrate dlcaprylate week gains to trace. l5 Lake water 2:0 One Week Two Weeks Three Weeks 2. 0 Roll- Roll- Roll- Cone ers Cone ers Cone ers T i Commercial grease M 8M M 9M 8 HM EXAMPLE 4 Grease of this 0 0 0 0 0 o This example provides comparative rust-inhibiting data on a gzz zfi i available greases marketed for The compounded grease was also tested using the modified 2 5 ASTM method, employing Pacific Ocean water. The same mlodlfied fi Salt water was employed commercial grease, as tested above, was also tested concure ts were as 0 rently. The results were as follows:

Grease-Forming Salt water Rusting Grease Agent one week One weei 'l w rfizre lfs Three Weeks Roll- Roll- Roll- A Anhydrous Calcium Severe rusting Cone Cone Cone Soap ZnO Z izsxtzifazzizr 2212:1223? S s S E Grease of this T 4M 1 2M 2M D Barium Soap ZnO Severe rusting exampla T 4M T 2M M 2M E Calcium Complex Severe rusting exam le '01- [T F Calcium Soap Severe rusting p G Barium Soap Severe rusting 40 In the two tables shown above the ratings had the following meaning: EXAMPLE 5 0 No corrosion =T Trace corrosion A. The base grease used in this example was a calcium sul- M: Moderate corrosion fonate grease prepared in accordance with the procedure S Severe rusting and metal penetration f t anddclamed i f 721719 The There were 12 rollers for each bearing. The number preced- 1c ploce we was as o ing the rating indicates the number of individual rollers rusted.

55 8 sulfonic acid For example, 128 means that all rollers were rusted severely. 82 g. 100 pale oil EXAMPLE 6 27.4 g. tap water The abovehsted materials were added to 3 34km. 3 necked This example illustrates the effectiveness of the rust-inhibitflask. An amount of 8.1 of Ca(oH)2 was added for ing additive combination of may invention in a hydrated calcineutralization using methyl alcohol for addition. The contents grease of the flasks were mixed well for 5 minutes. Then the amount A pressure type Sapomficzmon vessel (1) was charged of Ca(oH)2 for overbasing (675 was added to the flask the following materials to prepare concentrated soap stock: using methyl alcohol. A total amount of 174 g. of methyl al- 158 pounds Dlsnned Tallow ,Fatty Acids (2 coho! was used 23 pounds Calcium Hydroxide The admixture was blown with C0,, at a rate of about 4 g. 6 pounds per minute, for 20 minutes while maintaining the temperature 325 pounds (3) at 0 C. The contents were maintained at reflux tempera The vessel was closed and the total mass was stirred and ture for 30 minutes. The contents of the flask were transferred heated to ut F- Purmg heating the vessel pressure into a Hobart mixer and heated at reflux temperature (1 15 F.) creased to about 70 h was a lfqmd soap Much for 30 minutes. The admixture was then heated to 250 F. to was removed the Sapomfican? vessel mm an type remove solvents. A partial house vacuum was applied and the keme havmg counter'rotnng scraper type agltators' contents heated to a pot temperature of 325 F. The contents q water added whlle the hot Soap Stock was were cooled, 150 g of bright Stock (lubricating oil) was being agitated until at least 0.5 to 1.0 percent water could be added and the cooled to mom temperature while mixing maintained. Additional oil (488 pounds (4) was added slowly The yield of grease was 574 grams The product had an to the soap stock to make a finished base grease having a ASTM penetration at 77 F. of 287. Pmelrmion 265 (5 8. Using the base grease described in part A of this example A composition containing the above grease was blended as a grease was prepared having the following composition: follows:

95.5% (wt.) calcium sulfonate grease 573 pans above described grease 12 parts lead Naphthenate 9 parts didodecyl dimethyl quaternary ammonium nitrite (Arquad 2C Nitrite) 6 parts fatty imadazoline alkyl diamine dicaprylate (Nalco SCC 135) When tested in the modified ASTM D1743 rust test using Gulf ocean water, the bearing showed only trace rusting on one bearing after one week storage and no rusting after 2 weeks in storage.

1. Stratco contactor 2. Emery 531 3. A solvent neutral cycle oil having a viscosity of 144 StS.U. at 100 F. and 42 S.S.U. at 210 F.

4. A solvent neutral cycle oil having a viscosity of- 900 S.S.U. at 100 F. and 70 S.S.U. at 210 F.

5. ASTM D217 Method EXAMPLE 7 This example illustrates the effectiveness of the rust-inhibiting additive combination of my invention in an anhydrous calcium grease.

The following materials were charged to a double planetary open-type grease kettle 3200 parts Parafiinic Oil (S.S.U. 80 at 100 F.)

108 parts Calcium Hydroxide 108 parts Water 700 parts 12-l-lydroxystearic Acid The above mixture was heated slowly (over a period of 2 hours) to 260 F. Additional oil was added slowly (2,000 parts S.S.U. 80 parafiinic oil). The total mass was then passed through a Charlotte Colloid mill set at 0.003-inch clearance.

A compounded grease composition was prepared by adding to the entire amount of the base grease the following materials:

126 parts lead naphthenate 63 parts fatty imidazoline alkyl diamine dicaprylate (Nalco SCC 135) 94.5 parts didodecyl dimethyl quaternary ammonium nitrite (Arquad 2C Nitrite) The resulting grease had a penetration of 275. When tested in the modified ASTM D1743 rust test using Gulf ocean water, the test bearings exhibited only trace to no corrosion.

EXAMPLE 8 This example illustrates the effectiveness of the rust-inhibiting additive combination of my invention in a calcium sulfonate acetate complex grease.

The base grease was prepared by adding to an open-type planetary scraper-type grease vessel the following materials:

460 parts hyperbasic calcium sulfonate having an acetic base number of about 300 270 parts paraffinic bright stock oil (2,900 S.S.U. at 100 F.

and 155 S.S.U. at 210F.) The above mixture was heated and stirred to 180 F. at which time 50 parts of water were added. The above mass was agitated for approximately 30 minutes while maintaining a temperature of between 210 and 220 F. A mixture of 45 parts of glacial acetic acid and 55 parts of water was then added slowly to the above mixture. The total mass was then agitated for about 30 minutes while maintaining a temperature of between 210 and 220 F. Water was then removed by heating the kettle contents to 310 F. at which time 270 parts of the above described oil were added. The resulting grease was cooled to 235 F. and the following materials added:

21 parts Lead Naphthenetc l6 pans didodecyl dimethyl quaternary The resulting grease had a penetration of 267.

When tested in the modified ASTM D1743 rust test, using Gulf ocean water, the test bearings exhibited a trace to 0 moderate corrosion.

EXAMPLE 9 This example illustrates the effectiveness of the rust-inhibiting additive combination of my invention in a calcium sulfonate-acetate-fatty acid complex grease.

The base grease was prepared by adding to an open-type planetary scraper-type grease vessel the following materials:

249 parts hyperbasic calcium sulfonate having an acetic base number of about 300 96 parts parafl'inic Bright stock oil (same as in example 8) 1.25 parts methoxy ethanol 25 parts water The above mixture was stirred for 30 minutes while maintaining a temperature of 210 to 220 F. 5.45 parts of 12- hydroxystearic acid were added followed by a mixture of 24.3 parts glacial acetic acid and 30 parts water. This mixture was stirred for 30 minutes while maintaining a temperature of 210 220 F. The total mass was then heated to 310 F. to remove water and the following added:

97 pans paralfinic Bright Stock oil 43 parts paraffinic Pale Oil (S.S.U.

100 at 100 F.) 12.9 parts Lead Naphthenate 9.7 parts didodecyl dimethyl quaternary ammonium nitrite (Arquad 2C Nitrite) 6.5 parts Fatty imidazoloine alkyl diamine dicaprylzite (Nalco SCC The resulting grease had a penetration of 271.

When tested in the modified ASTM D-l743 rust test, using Gulf ocean water, the test bearings exhibited only a trace to no corrosion.

The rust-inhibiting additive composition of my invention has not been found to be efiective in preventing salt water corrosion when added to lithium-base greases. For this reason it is believed that the additive composition is specific for calcium greases It is to be understood that various other additives which are normally used in greases can be used in my greases. Examples of these additives include oxidation inhibitors, lubricating agents, extreme pressure agents, stringiness agents and the like.

While particular embodiments of the invention have been described, it will be understood, of course, that the invention is not limited thereto, since many modifications may be made; and it is, therefore, contemplated to cover by the appended claims any such modifications as fall within the true spirit and scope of the invention.

The invention having been described, what is claimed and desired to be secured by Letters Patent is:

l. A grease composition consisting essentially of a calcium base grease, made with a mineral lubricating oil. containing synergistic rusteinhibiting proportions of a combination of lead naphthenate, a fatty imidazoline alkyl diamine dicapry late prepared from a fatty imidazoline alkyl diamine having the structure wherein R is mixed heptadecenyl or mixed heptadecadienyl, and a dialkyl dimethyl quaternary ammonium compound represented by the formula wherein R and R, are C to C alkyl groups and X is nitrite or nitrate.

2. The grease composition of claim 1 wherein the lead naphthenate is present in an amount of from about I to 3 percent by weight, the fatty imidazoline alkyl diamine dicaprylate is present in an amount of from about 0.5 to about 2 percent by weight and the dialkyl dimethyl quaternary ammonium compound is present in an amount of from about 1 to about 4 percent by weight.

3. The grease composition of claim 2 wherein the base grease is a calcium sulfonate grease.

4. The grease composition of claim 2 wherein the base grease is a calcium soap grease.

5. A grease composition consisting essentially of a calcium base grease, made with a mineral lubricating oil, containing synergistic rust-inhibiting proportions of a combination of lead naphthenate, a fatty imidazoline alkyl diamine dicaprylate prepared from a fatty imidazoline alkyl diamine having the structure wherein R is mixed heptadecenyl or mixed heptadecadienyl, and a dialkyl dimethyl quaternary ammonium compound represented by the formula where R and R are C to C alkyl groups and X is nitrite or greaseisacalcium sulfonate grease. I

The grease composition of claim 6 wherein the base grease is a calcium soap grease. 

2. The grease composition of claim 1 wherein the lead naphthenate is present in an amount of from about 1 to 3 percent by weight, the fatty imidazoline alkyl diamine dicaprylate is present in an amount of from about 0.5 to about 2 percent by weight and the dialkyl dimethyl quaternary ammonium compound is present in an amount of from about 1 to about 4 percent by weight.
 3. The grease composition of claim 2 wherein the base grease is a calcium sulfonate grease.
 4. The grease composition of claim 2 wherein the base grease is a calcium soap grease.
 5. A grease composition consisting essentially of a calcium base grease, made with a mineral lubricating oil, containing synergistic rust-inhibiting proportions of a combination of lead naphthenate, a fatty imidazoline alkyl diamine dicaprylate prepared from a fatty imidazoline alkyl diamine having the structure wherein R is mixed heptadecenyl or mixed heptadecadienyl, and a dialkyl dimethyl quaternary ammonium compound represented by the formula wherein R and R1 are C9 to C17 alkyl groups and X is nitrite or nitrate, said lead naphthenate being present in an amount of from about 1.5 to about 2.5 percent by weight, said fatty imidazoline alkyl diamine dicaprylate being present in an amount of from about 0.75 to about 1.25 percent by weight and said dialkyl dimethyl quaternary ammonium compound being present in an amount from about 1.25 to about 2 percent by weight.
 6. The grease composition of claim 5 wherein the quaternary ammonium compound is didodecyl dimethyl quaternary ammonium nitrite.
 7. The grease composition of claim 6 wherein the base grease is a calcium sulfonate grease.
 8. The grease composition of claim 6 wherein the base grease is a calcium soap grease. 